Take-off tool



Jan. 28, 1969 M. w. K EY MER TAKE-OFF TOOL Filed Jan. 24, 1966 3 FIG. 4.

FIG. 3

FIG. 6

v INVENTOR. M1451. M KEY/U56 ,4 TTdE/UEVS United States Patent 3,423,984 TAKE-OFF TOOL Mark W. Keymer, Hopkins, Minn., assignor to Malco Products, Inc., Minneapolis, Minn., a corporation of Minnesota Filed Jan. 24, 1966, Ser. No. 522,458

US. Cl. 72-337 Int. Cl. B21d 9/08, 28/26 8 Claims ABSTRACT OF THE DISCLOSURE This invention relates to a take-off tool and more particularly relates to a take-off tool for use by heating and ventilating tradesmen in joining sections of metal ducts.

In the construction of a heating and ventilating system, or in the construction of an air conditioning system, it is necessary to connect lateral ducts to trunk ducts. The tradesman, in order to accomplish this task, typically places a template over the trunk duct and traces the configuration of the lateral duct to be inserted into the trunk. The lateral duct which is inserted may be of any of several shapes, but is typically round. The lateral member is notched at the ends, inserted into the aperture, and the notched portions are then bent to engage the trunk duct.

In performing this operation it is desirable to employ a tool which not only cuts the lateral duct, but also forms a bead on the outside of the lateral duct to secure the lateralto the trunk. The projecting bead engages the outer surface of the trunk duct and provides a clamping relation with the wall of the trunk duct, the jaws of the clamp being formed out by the bead on the outside of the wall and the folded tab on the inside of the wall. It is desirable to perform this operation with a minimum of steps and effort. Further, the finished take-off should appear neat and should be a tight fit to avoid any air loss through the 'oint. I With these comments in mind it is to the elimination of these and other disadvantages to which the present invention is directed along with the inclusion therein of other novel and desirable features.

An object of my invention is the provision of a new and improved take-off tool of simple and in expensive construction and operation.v

Another object of my invention is the provision of a take-off tool which notches and raises a head in one operation, providing a clamping jaw for tight fit to a trunk duct.

Another object of my invention is the provision of a tool which is designed to provide the tradesmen with compound leverage for ease in cutting and forming metal ducts.

Still another object of my invention is the provision of a tool which includes an adjustable guide to allow the tradesman to set the tool at a predetermined notch length so that each notch on a lateral duct may be made at the same lengh without the need for measuring each individual notch.

These and other objects and advantages of my invention will more fully appear from the description made in connection with the accompanying drawings wherein like refice erence characters refer to the same or similar parts throughout the several views, and in which:

FIG. 1 is a perspective view of the take-off tool of my invention.

FIG. 2 is a partial perspective view showing a lateral duct joined to a trunk duct after being notched and formed with the tool of my invention.

FIG. 3 is a partial enlarged sectional view showing the cutting and beading assembly of my invention before forming a lateral duct.

FIG. 4 is a partial enlarged sectional view showing the cutting and beading assembly of my invention in operation on a lateral duct.

FIG. 5 is a sectional view taken along the section line 55 of FIG. 3.

FIG. 6 is a partial perspective view showing a lateral duct cut and beaded with my tool.

One form of the present invention is shown in the drawings and is described herein.

The take-off tool of my invention is indicated in FIG. 1 by numeral 10 and includes a pair of grips 11 and 12. Vinyl sleeves may be fashioned to fit over the tool steel grips. A pivot is provided at 13 joining the grips 11 and 12. As pressure is applied to grips 11 and 12 through pivot 13 the mechanical action is transmitted to upper and lower jaws 14 and 15, respectively, which are interconnected with grips 11 and 12. Pivot 16 provides compound leverage at jaws 14 and 15 from the pressure exerted on grips 11 and 12. A lock 17 is provided to secure the tool in a storage position when not in use. The grips are spring-loaded (not shown) and the lock maintains the spring under compression when the tool is not in use.

A gauge 18 is provided and may be adjusted by screw 19, providing means for setting the notch distance as indicated by the dimension X. Gauge 18 is a metal gauge notched at 20 for shiftable movement on screw 19. A stop member 21 protrudes upwardly, preventing material to be cut from entering jaws 14 and 15 beyond the point at which member 21 is set.

The tool is constructed of properly heat treated tool steel, designed for long life when cutting sheet metal of approximately 24 gauge. Jaws 14 and 15 are heat treated and are constructed from tool steel.

Referring to FIG. 2, a trunk duct is indicated at 22 and a lateral duct 23 is shown joined to the trunk 22. The lateral 23 has been cut and beaded with take-off tool 10. One end of the lateral 23 is shown at it is joined to duct 22 with tabs 24 bent over to engage the wall 22a of duct 22, forming a clamp between the tabs 24 and protruding beads 25 with wall 22a sandwiched therebetween. The breakaway portion shows the relation between the bead and the tab.

FIG. 3 shows the upper and lower jaws 14 and 15 as they would appear about to engage duct 23 to be notched and beaded. The material of duct 23 is typically a 24 gauge sheet metal used in forming heating and ventilating ducts. Upper jaw 14 includes a transverse cutting edge 27 and a pair of longitudinal cutting edges 28 spaced apart by the width of solid jaw blade 14, only one of the edges 28 appearing in FIG. 3. The bead 25 is formed by protruding portion or nose 29 as it engages the mating socket 30 on lower jaw 15. Lower jaw 15 includes a pair of spaced, opposed parallel cutting edges 31 which cooperate with the cuting edges 28, and a transverse cutting edge 31a which cooperates with edge 27 to provide a shearing action to cut away a predetermined portion of the lateral 23 providing a slot.

FIG. 4 shows the upper and lower jaws 14 and 15 after the cutting and heading operation has been performed on the lateral. The waste material 32 is shown falling through lower jaw 15. The bead 25 is shown formed in socket 30 by mating nose 29. The cutting surfaces 31 of of jaw 15 are shown in FIG. 5. An opening is provided with an increased dimension, as indicated by Y, to allow waste material 32 to readily pass through jaw 15. Since dimension Y increases as piece 32 falls through, there is considerably less possibility of jamming of material when notching ducts.

FIG. 6 shows a portion of lateral 23 after the cutting and beading operation has been performed. The bead 25 is shown as a depressed area. Tabs indicated at 24 are folded to engage the inner surface of the trunk duct forming a clamp with beads 25, the wall of the trunk sandwiched therebetween. The dimension Z is typically equivalent to the thickness of a trunk duct, generally about 24 gauge. This affords the tightest possible fit between the lateral and trunk duct, thereby eliminating heat or cooling loss and providing a joint of improved appearance.

In the operation of my take-off tool, the tradesman simply releases lock 17 which maintains the spring of grips 11 and 12 in compression. The allows mating jaws 14 and 15 to assume a normally open position. Set screw 19 is loosened, and the tradesman sets the adjustable stop 18 at the predetermined setting, dependent upon the length of the notch which the tradesman wishes to make. Set screw 19 is then secured, maintaining this predetermined setting as the operator procedes to notch and bead a lateral duct. The lateral duct 23 is inserted into jaws 14 and 15 up to stop member 21, taking care that the axis of the duct and the notches to be made are substantially parallel. Next the operator squeezes grips 11 and 12, and since the tool provides compound leverage between pivots 13 and 16, 24 gauge material is easily cut and beaded. Longitudinal cutting surfaces 28 and transverse cutting surface 27 on jaw 14 cooperate with the cutting surfaces 31 and 31a to provide a shearing action cutting and discharging waste piece 32, forming a slot in lateral 23. Simultaneously protruding portion 29 on upper jaw 14 engages the lateral duct 23 and forces it into socket 30 on lower jaw 15, forming a bead or dimple. The operator continues to do this until the lateral duct has the desired number of tabs 24 and beads 25.

Next the tradesman slips the lateral duct into an opening in the truck duct, which opening corresponds with the configuration of the lateral duct. The tradesman then bends tabs 24 to engage the wall 22a of the trunk duct 22, securing lateral duct 23 by clamping the wall 22a of the trunk duct 22 between the tabs 24 and dimples 25.

The operator, upon completion of the notching and beading operation, may return the tool to its locked position, compressing the spring.

It will, of course, be understood that various changes may be made in the form, details, arrangement and proportions of the various parts without departing from the scope of my invention.

What is claimed is:

1. A take-off tool adapted to prepare rigid, bendable duct material and the like for connection to a duct wall, the take-off tool comprising,

a pair of pivotally connected grip members,

an upper jaw member interconnected with one of said grip members, said upper jaw including longitudinal erally forwardly of said longitudinal cutting means of said lower jaw, said socket portion adapted to receive said protruding portion of said upper jaw whereby a raised portion may be provided on the duct material.

2. The take-off tool of claim 1 wherein said pair of grip members are interconnected with said pair of jaw members through a plurality of pivot points to permit compound leverage between said grip members and said jaw members.

3. The take-off tool of claim 1 including a gauge shiftably mounted on said tool, said gauge adapted to be secured in a predetermined position to permit cutting duct material at a constant, predetermined length.

4. The take-off tool of claim 1 wherein said lower jaw includes a longitudinal opening therethrough adapted to receive and discharge waste duct material.

5. The take-off tool of claim 1 wherein said pair of grip members includes a spring adapted to maintain said jaw members in a normal open position.

6. The take-off tool of claim 5 wherein said take-off tool includes a lock mounted on said tool whereby said pair of spring loaded grip members may be locked with said jaw members in a closed position, permitting storage of the spring under compression.

7. The take-off tool of claim 4 wherein said opening increases in width downwardly from said longitudinal cutting means to the discharge side thereof to permit clearance for the waste material.

8. The take-off tool of claim 1 wherein said upper jaw member has a solid blade and said longitudinal cutting means comprises two, elongate, cutting edges on the opposite sides thereof, and

said lower jaw member has an elongated opening therein, with said longitudinal cutting means comprising two, spaced apart, cutting edges on the opposite sides of said opening, whereby said upper jaw member may be received within said opening to cut a longitudinal notch in duct material.

References Cited UNITED STATES PATENTS 9/1943 Schweidler 72-332 3/1957 Seher 72-332 

